In the manufacture of a flat panel display (FPD) such as a liquid crystal display (LCD) or a plasma display panel (PDP), processes for forming various kinds of patterns such as electrodes or black matrix, color filters, separators, thin film transistors and the like are required.
As the pattern forming process, a method for forming a pattern by using a photosensitive resist and a photomask to obtain a photosensitive resist pattern which is selectively removed through exposure and development and using the same has been often used. The photomask process has a problem in that a material such as photosensitive resist or developing solution is often used, an expensive photomask needs to be used, and many processing steps need to be performed or the process time is prolonged.
In order to solve the problem, there have been proposed methods for printing a pattern-forming material directly, such as a method by inkjet printing or laser transfer, without using a photosensitive resist. As one of such methods, there is an offset printing method in which a patterned material is transferred to a blanket using a cliché and then the pattern of the blanket is transferred to a substrate.
The offset printing method using a cliché is advantageous in that the material consumption is less and the process is simpler than a method in the related art using a photosensitive resist and the process speed is faster than inkjet printing or laser transfer. However, the offset printing method is disadvantageous in that clichés are needed respectively for substrates with different patterns and manufacturing clichés usually made of glass are a complicated and expensive process.
The following FIG. 1 schematically illustrates a reverse offset printing process and a gravure offset printing process. In the case of a cliché in the related art (in the case of a reverse offset and a gravure offset), a method for manufacturing a cliché by using a mask raw material has been usually used. However, when a thick cliché is used in this manner, patternability is greatly affected by the occurrence of a phenomenon that the cliché is pushed during the off time from the cliché according to the driving mode of a printing apparatus. In order to solve this, when a cliché is manufactured by using a photolithography process in the related art through a mask, the cliché has a problem in that the smallest line width of the cliché depends on the ability to implement an exposing machine and to implement a mask and simultaneously, the manufacturing cost thereof is very high due to costs of the mask, the exposing machine and the like.